FXUS62 KTAE 011518
AFDTAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1015 AM EST TUE DEC 1 2009
...CONFIDENCE INCREASING IN A SIGNIFICANT WEATHER EVENT STARTING
TONIGHT AND CONTINUING THROUGH WEDNESDAY...
.DISCUSSION...
14Z WATER VAPOR AND H4 RUC ANALYSIS SHOWING AN INCREASINGLY COMPLEX
UPPER LEVEL PATTERN ACROSS THE CONUS. NORTHERN STREAM FLOW IS
LOCATED WELL TO OUR NORTH WITH ONE SHORTWAVE EXITING THE NORTHEAST
COAST AND ANOTHER DIVING SOUTH ACROSS THE NORTHERN PLAINS. OF MORE
IMMEDIATE CONCERN AND INTEREST IS THE POTENT UPPER LEVEL SYSTEM
CROSSING NORTHERN MEXICO AND TEXAS. ABUNDANT UPPER LEVEL MOISTURE IS
STREAMING EAST AND NORTHEAST AHEAD OF THIS SYSTEM AND WILL CONTINUE
TO INCREASE THE CLOUDS OVERHEAD THROUGH THE DAY.
AT THE SURFACE...UPPER LEVEL ENERGY ACROSS TEXAS IS BEGINNING TO
INTERACT WITH THE WESTERN GULF BAROCLINIC ZONE. SURFACE PRESSURE
HAVE BEEN FALLING AND NOW SEEING A DEEPENING 1006MB AREA OF LOW
PRESSURE OFF THE TEXAS COAST.
LOW PRESSURE WILL CONTINUE TO EVOLVE THROUGH THE AFTERNOON AND
EVENING AS IT MOVES NORTHEAST TO NEAR THE SOUTHERN LA COAST. WARM
FRONT DEVELOPING TO ITS EAST ACROSS THE CENTRAL/EASTERN GULF OF
MEXICO WILL BEGIN TO TRANSLATE NORTHWARD LATER TODAY AND APPROACH
THE PANHANDLE COAST THIS EVENING. AS MENTIONED ABOVE...CLOUDS WILL
CONTINUE TO INCREASE AND ANY LINGERING SUNSHINE ACROSS OUR GA ZONES
SHOULD END BY MID AFTERNOON. DEEP LAYER ISENTROPIC UPGLIDE WILL BE
INCREASING ALONG AND NORTH OF THE SURFACE WARM FRONT THROUGH THIS
AFTERNOON...HOWEVER IT WILL TAKE SOME TIME TO MOISTEN THE COLUMN
ENOUGH TO START PRODUCING PRECIP. MOST LOCATIONS WILL NOT SEE ANY
RAINFALL DURING THE DAYLIGHT HOURS...HOWEVER A FEW SHOWERS ARE
CERTAINLY POSSIBLE ACROSS THE EASTERN PANHANDLE...ESPECIALLY NEAR
THE COAST AFTER 3 OR 4 PM.
THE REAL ACTION IS ANTICIPATED TO GET GOING AFTER SUNDOWN THIS
EVENING AS THE WARM FRONT REACHES THE COAST AND BEGINS TO SPREAD
INLAND. IMPRESSIVE UPGLIDE WILL COMBINE WITH INCREASING SYNOPTIC
LIFT AND DIVERGENT FLOW ALOFT TO PRODUCE A BAND OF POTENTIAL HEAVY
RAINFALL TO THE EAST AND NORTHEAST OF THE LOW CENTER. THE EXACT
TRACK OF THIS LOW DETERMINE JUST WHERE THIS BAND SETS UP...
HOWEVER...CONFIDENCE IS INCREASING THAT AT LEAST A PORTION OF THE
HEAVIER BAND WILL OCCUR ACROSS SOME OF OUR EASTERN PANHANDLE
SOUTHEAST ALABAMA...AND SOUTHWEST GA ZONES. FLOOD WATCHES ARE IN
EFFECT FOR THESE AREAS AND A REGION OF 4 TO 6 INCHES WITH LOCALLY
HIGHER AMOUNTS IS ANTICIPATED.
THE THREAT OF SEVERE WEATHER WILL ALSO BE INCREASING ACROSS THESE
ZONES. ALTHOUGH SURFACE INSTABILITY IS STILL A BIT IN QUESTION...
CONVECTIVE CELLS WILL BE ENCOUNTERING A HIGHLY SHEARED ENVIRONMENT.
DEPENDING ON THE SURFACE INSTABILITY...THERE IS A THREAT OF ISOLATED
TORNADOES WITH THESE STORMS...ESPECIALLY ALONG AND JUST NORTH OF THE
SURFACE WARM FRONT WHERE LOW LEVEL HODOGRAPHS WILL BE MOST
CONDUCIVE. ALTHOUGH LAPSE RATES ALOFT ARE NOT ALL THAT IMPRESSIVE...
THE SHEAR IS CERTAINLY SUFFICIENT TO SUPPORT ORGANIZED UPDRAFTS AND
LARGE HAIL CAN NOT BE RULED OUT.
AS THE SURFACE LOW LIFTS TO OUR NORTHEAST DURING WEDNESDAY AND THE
ASSOCIATED COLD FRONT BEGINS TO TRANSLATE EASTWARD...CONFIDENCE IS
ALSO INCREASING IN THE DEVELOPMENT OF A SQUALL LINE OF STRONG TO
POTENTIALLY SEVERE STORMS WITHIN THE WARM SECTOR. THIS SQUALL LINE
SHOULD MOVE EAST ACROSS THE FORECAST AREA DURING THE DAYLIGHT HOURS.
PLENTY OF ENERGY TO SUPPORT THE CONTINUED EVOLUTION OF THIS LINE
EVEN INTO OUR EASTERN ZONES WITH INCREASING LARGE SCALE ASCENT AND
A HIGH SHEAR ENVIRONMENT. LLJ OF 60-70 KNOTS WILL PRESENT THE
POSSIBILITY OF DAMAGING STRAIGHT LINE WINDS WITH THIS LINE. AN
ISOLATED TORNADIC THREAT WILL ALSO CONTINUE AND WILL HAVE TO
MONITORED CLOSELY.
COASTAL EFFECTS...VERY LITTLE HAS CHANGED WITH THE THINKING FOR
COASTAL FLOODING OR HIGH SURF WITH THIS SYSTEM. STRONG ONSHORE WINDS
WILL BEGIN ACROSS THE MARINE AREA ON TUESDAY EVENING AND BEGIN TO
CREATE HIGH SURF. AS THESE WINDS TURN FULLY ONSHORE BY 12
WEDNESDAY...A 12 HOUR PERIOD OF NEAR GALE FORCE WINDS WILL KEEP
WATER LEVELS CONSIDERABLY ELEVATED AND PRODUCE A PERIOD OF
INUNDATION AROUND THE TIMES OF HIGH TIDE. WHILE THE BEST SURGE OF
HIGHER WATER APPEARS TO LINE UP WITH THE TIMES OF LOW TIDE WEST OF
GULF COUNTY...IT IS DIRECTLY LINED UP WITH THE TIME OF HIGH TIDE IN
APALACHEE BAY. THUS...LOCALLY MORE SIGNIFICANT INUNDATION IS
POSSIBLE FROM PORTIONS OF FRANKLIN COUNTY EASTWARD TO THE SUWANNEE
RIVER ENTRANCE. OVERALL STORM TIDES ALONG FRANKLIN COUNTY COULD
REACH UP TO 3 TO 4 FEET...WITH 5 TO 7 FEET POSSIBLE BETWEEN SAINT
MARKS AND THE SUWANNEE RIVER ENTRANCE.
LARGE AND DANGEROUS SURF WILL ALSO BEGIN TO AFFECT THE BEACHES OF
WALTON...BAY...GULF AND FRANKLIN COUNTIES LATE TUESDAY NIGHT AND
EARLY WEDNESDAY MORNING. SURF HEIGHTS ARE CURRENTLY PREDICTED TO
PEAK AT 10 TO 12 FEET FROM WALTON COUNTY EASTWARD TO MEXICO BEACH
WITH SLIGHTLY LOWER TOTALS TO THE SOUTHERN END OF THE ST. JOSEPH
PENINSULA. THUS...IN THIS AREA WILL ISSUE A HIGH SURF WARNING. FOR
FRANKLIN COUNTY...LOWER SURF HEIGHTS ARE EXPECTED...THOUGH STILL
HIGH ENOUGH TO CAUSE BEACH EROSION ON ST GEORGE ISLAND. WILL ISSUE
A HIGH SURF ADVISORY FOR THIS AREA.
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGH THE REMAINDER OF THE DAY TODAY.
HOWEVER...CONDITIONS WILL DETERIORATE QUICKLY THIS EVENING WITH MVFR
CIGS/VSBY OVERSPREADING THE FORECAST AREA DURING THE 00-02Z TIME
FRAME. THESE WILL EVENTUALLY BECOME THE PREVAILING CONDITIONS AND
PERIODS OF IFR CONDITIONS ARE ANTICIPATED DURING THE 2ND HALF OF THE
NIGHT IN HEAVIER SHOWERS AND STORMS. WINDS WILL ALSO GET QUITE GUSTY
WITH GUSTS AS HIGH AS 30-35 KT AT PFN AND DHN.
&&
.MARINE...A VERY UNSETTLED PERIOD OVER THE MARINE AREA IS ALREADY
UNDERWAY WITH EXERCISE CAUTION CONDITIONS OCCURRING. EXPECT WINDS TO
SLOWLY INCREASE THROUGHOUT THE DAY AND BUILD TO NEAR GALE FORCE...AT
LEAST IN GUSTS...ACROSS THE WESTERN WATERS TOWARD MIDNIGHT. WINDS
WILL INCREASE TO NEAR GALE FORCE IN THE EASTERN WATERS BY SUNRISE.
THESE WINDS WILL CREATE EXTREMELY HIGH SEAS...WITH THE LOCALLY RUN
SWAN GUIDANCE PEAKING AT 22 FEET WELL OFFSHORE. WILL BACK OFF THESE
VALUES A LITTLE...BUT IN ANY EVENT DANGEROUSLY HIGH SEAS ARE
EXPECTED. ONCE THE SURFACE LOW MOVES INTO THE TENNESSEE VALLEY...THE
PRESSURE GRADIENT WILL WEAKEN ENOUGH FOR WINDS TO DECREASE BELOW
GALE FORCE...THOUGH A PERIOD OF SCA CONDITIONS WILL CONTINUE UNTIL
AT LEAST MIDDAY THURSDAY. ALTHOUGH WINDS ARE EXPECTED TO
DIMINISH...SOUTHERLY SWELL WHEN WINDS AND SEAS WILL FINALLY DROP BELOW
HEADLINE CRITERIA.
&&
.HYDROLOGY...A FLASH FLOOD WATCH HAS BEEN ISSUED FOR AREAS TO THE
WEST OF INTERSTATE 75. THE BEST THREAT FOR URBANIZED FLOODING LOOKS
TO BE IN AREAS FROM US-19 IN GEORGIA WESTWARD INTO SOUTHEAST ALABAMA
AND INTO THE FLORIDA PANHANDLE WHERE THE HEAVIEST RAIN IS CURRENTLY
PREDICTED. WITH RAINFALL TOTALS IN THIS AREA POSSIBLY UP TO 8
INCHES...RIVER FLOODING ON THE MAIN RIVERS AND SMALLER CREEKS IS
POSSIBLE IN THE DAYS AHEAD. PLEASE REFER TO THE HYDROLOGIC OUTLOOK
ISSUED BY THIS OFFICE ON MONDAY AFTERNOON FOR MORE DETAILS ON
SPECIFIC RIVER BASINS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TALLAHASSEE 66 61 72 50 64 / 10 60 100 40 10
PANAMA CITY 67 63 72 51 62 / 40 90 100 20 10
DOTHAN 60 56 69 47 60 / 20 90 100 10 10
ALBANY 60 57 69 48 63 / 10 90 100 30 10
VALDOSTA 64 60 72 51 65 / 10 60 100 60 10
CROSS CITY 68 62 73 56 68 / 10 40 100 70 10
APALACHICOLA 67 64 73 51 63 / 40 70 100 40 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...FLASH FLOOD WATCH FROM 9 PM CST THIS EVENING THROUGH WEDNESDAY
EVENING FOR THE FOLLOWING ZONES: COFFEE...DALE...GENEVA...
HENRY...HOUSTON.
GA...FLASH FLOOD WATCH FROM 10 PM EST THIS EVENING THROUGH LATE
WEDNESDAY NIGHT FOR THE FOLLOWING ZONES: BAKER...CALHOUN...
CLAY...COLQUITT...DECATUR...DOUGHERTY...EARLY...GRADY...
LEE...MILLER...MITCHELL...QUITMAN...RANDOLPH...SEMINOLE...
TERRELL...THOMAS...WORTH.
FL...FLASH FLOOD WATCH FROM 10 PM EST /9 PM CST/ THIS EVENING THROUGH
LATE WEDNESDAY NIGHT FOR THE FOLLOWING ZONES: BAY...
CALHOUN...COASTAL WALTON...FRANKLIN...GADSDEN...GULF...
HOLMES...INLAND WALTON...JACKSON...JEFFERSON...LEON...
LIBERTY...WAKULLA...WASHINGTON.
HIGH SURF ADVISORY FROM 1 AM WEDNESDAY TO 1 AM EST THURSDAY FOR
THE FOLLOWING ZONES: FRANKLIN.
HIGH SURF WARNING FROM MIDNIGHT TONIGHT TO MIDNIGHT CST
WEDNESDAY NIGHT FOR THE FOLLOWING ZONES: BAY...COASTAL
WALTON...GULF.
GM...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST
WEDNESDAY FOR THE FOLLOWING ZONES: APALACHEE BAY OR COASTAL
WATERS FROM KEATON BEACH TO OCHLOCKONEE RIVER FL OUT TO 20
NM...COASTAL WATERS FROM OCHLOCKONEE RIVER TO APALACHICOLA
FL OUT TO 20 NM...COASTAL WATERS FROM SUWANNEE RIVER TO
KEATON BEACH OUT 20 NM...WATERS FROM SUWANNEE RIVER TO
APALACHICOLA FL FROM 20 TO 60 NM.
SMALL CRAFT ADVISORY FROM 7 PM WEDNESDAY TO 1 PM EST THURSDAY
FOR THE FOLLOWING ZONES: APALACHEE BAY OR COASTAL WATERS
FROM KEATON BEACH TO OCHLOCKONEE RIVER FL OUT TO 20 NM...
COASTAL WATERS FROM OCHLOCKONEE RIVER TO APALACHICOLA FL
OUT TO 20 NM...COASTAL WATERS FROM SUWANNEE RIVER TO KEATON
BEACH OUT 20 NM...COASTAL WATERS FROM APALACHICOLA TO
DESTIN FL OUT 20 NM...WATERS FROM SUWANNEE RIVER TO
APALACHICOLA FL FROM 20 TO 60 NM...WATERS FROM APALACHICOLA
TO DESTIN FL FROM 20 TO 60 NM.
GALE WARNING FROM 7 AM TO 7 PM EST WEDNESDAY FOR THE FOLLOWING
ZONES: APALACHEE BAY OR COASTAL WATERS FROM KEATON BEACH TO
OCHLOCKONEE RIVER FL OUT TO 20 NM...COASTAL WATERS FROM
OCHLOCKONEE RIVER TO APALACHICOLA FL OUT TO 20 NM...COASTAL
WATERS FROM SUWANNEE RIVER TO KEATON BEACH OUT 20 NM...
WATERS FROM SUWANNEE RIVER TO APALACHICOLA FL FROM 20 TO 60
NM.
SMALL CRAFT ADVISORY UNTIL 1 AM EST WEDNESDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM APALACHICOLA TO DESTIN FL OUT 20
NM...WATERS FROM APALACHICOLA TO DESTIN FL FROM 20 TO 60 NM.
GALE WARNING FROM 1 AM TO 7 PM EST WEDNESDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM APALACHICOLA TO DESTIN FL OUT 20
NM...WATERS FROM APALACHICOLA TO DESTIN FL FROM 20 TO 60 NM.
&&
$$
SYNOPSIS/DISCUSSION...MROCZKA
AVIATION...WOOL
COASTAL EFFECTS/MARINE...GODSEY/MROCZKA
